1. Field of the Invention
The present invention relates to tin-plated copper-alloy material for terminal and a method for producing the same that is used for connecting electrical wiring of automobiles or personal products, in particular, that is useful for a terminal for a multi-pin connector. Priority is claimed on Japanese Patent Application No. 2012-014380, filed Jan. 26, 2012, the content of which is incorporated herein by reference.
2. Description of Related Art
Tin-plated copper-alloy material for terminal is formed by reflowing after Cu-plating and Sn-plating on a substrate made of copper alloy so as to have a Sn-based surface layer as a surface layer and a Cu—Sn alloy layer as a bottom layer, and is widely used as material for terminal.
In recent years, for example, electrization is rapidly progressed in vehicle and circuits are increased in the electrical equipment, so that connector used in the circuit is remarkably downsized and the pins thereof are increased. When the connector have a lot of pins, even though a force for engaging the connector for a pin is small, since a large force is required for engaging the connector for all pins, it is apprehended that productivity is deteriorated. Therefore, it is attempted to decrease the force for engaging for a pin by reducing the friction coefficient of tin-plated copper-alloy material.
For example, in Japanese Unexamined Patent Application, First Publication No. 2007-100220, a surface-exposure rate of the Cu—Sn alloy layer is configured by roughing the substrate. However, there are problems of increasing contact resistance or decreasing wettability of solder. Also, in Japanese Unexamined Patent Application, First Publication No. 2007-63624, average of surface roughness of the Cu—Sn alloy layer is configured. However, for example, there is a problem in which a coefficient of kinetic friction cannot be reduced to not more than 0.3 for further improving easiness of engaging and disengaging the connector.